Improvement in piano-forte actions



J. W. EVANS. PIANO-FORTE ACTIONS.

N- PETERS, PHOTO-LITHDGRAFHER, WASQINGTON, D C.

Patented July 24,1877.

UNITED STATES JOHN W. EVANS, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN PIANO-FORTE ACTIONS.

Specification forming part of Letters Patent N o. EJ3 2325. dated July 24, 1877; application filed February 5, 1877.

To all whom it may concern Be it known that I, JOHN W. EVANS, of

Chicago, in the county of Cook and State of Illinois, have invented certain Improvements in Piano-Fortes, of which the following is a specification Piano-makers have experienced a great deal of trouble from the loosening of the fastenings of the action devices, caused by the shrinking and expanding of the wooden parts of the action under varying atmospheric conditions. A very inconsiderable amount of moisture in the air beyond the normal amount will cause the wood to expand. This does no particular harm; but when the air becomes dry again, and thereby dries the wood, it causes a shrinkage back to its original size, and leaves all the fastenings loose. The delicate nature of the mechanism is such that a very slight displacement of the parts will render it inoperative. I y

The joints in a piano-forte action most likely to be loosened by the weather are those where screws are employed to secure one piece of Wood to another. Such joints or fastenings occur between what is termed the jack and the key, between the hammer-rail and the hammer-flange, and between the damper-rail and the damper-flange, as actions are now commonly constructed.

In the present invention I obviate this liability of the screw-fastened connections to shrink loose by interposing at some point in the joint a piece of india-rubber, which is compressed by the screw or screws that fast ens the pieces of wood together, and when the shrinkage occurs this compressed piece of rubber expands, and thus takes up the slack.

In the accompanying drawing, which forms a part of this specification, is shown a side view of a common piano-forte action.

In said drawing, Ais the key. B is the jack. 0 is the hammer. D is the hammerflange. Eis the hammer-rail. Fis the damperflange, and-G is the damper-rail. H is the damper..

The base of the jack B is secured to he key by screws a a. Between this base nd the upper part of the key is interposed a pi cc of india-rubber, M, and I set the screws tig a ly home to bring a considerable pressure to b ar 'upon the rubber.

The hammer-flange D is fastened to he hammer-rail E by a screw, a, and the dam r flange F in like manner to the damper-rail y a screw, a Between these flanges and t ir respective rails rubber is interposed, pref ably in long strips M M, which may be plaed in grooves in the upper surface of the r i1, and may extend the whole length of the r il, the same strips serving in such case for ll the flanges attached to the rail. The rub er is thus very easily and quickly applied.

When the screws are set home tightly he flanges are held secure at all times with danger of loosening.

In addition to the piece or pieces of rub er interposed between the pieces of wood, I so times apply a rubber Washer to the screw, 6- tween the head and the wood, which acts in conjunction with the rubber between the pie es of wood, and sometimes I use only the wasl er without the other piece or pieces. The was er alone is more convenient where pianos alre ly built are to be supplied with this impro ement.

I am well aware that flexible washers, of leather and similar materials, have been u d npon bolts for producing friction, and to ll out a vacant space. Such I do not claim as my invention.

That which I claim as new and my inv ntion is The piano-forte action in which the riid wooden joints are provided with a compressed spring for compensating the shrinkage of the wood, substantially as specified.

J. W. EVANS.

Witnesses JOHN W. MUNDAY, Fonnn B. SMITH. 

